With great media centre applications like Boxee, XBMC, and Plex for OS X, it's more tempting than ever to hook your Mac up to your HDTV. Now that you've upgraded from Leopard to Snow Leopard, you'll find Snow Leopard's gotten HDTV-friendly.
All-things-Apple weblog TUAW noticed that when you hook a MacBook up to an HDTV in Snow Leopard, you'll get new display options specifically tailored for your HDTV to display in 720p, 1080i, and good ol' 1080p. It's a minor tweak (you could always output at 1920×1080, but this is a friendlier option), but it's a handy one for folks using Macs as the hub of their home theatre setup, and this kind of tight integration between our computers and living rooms is the kind of thing we hope to only see more of in the future.
TUAW points out that they've tested it and found it working on machines connected via DisplayPort -> HDMI, but commenters on the post also confirm it working on DVI-to-HDMI adapters. If you give it a try, let's hear what's working for you in the comments.